Bending head attachments for hand-held power tools are known in the art and are useful in metalworking applications such as, for example, automotive body repair work, curtain wall systems installation and air duct assembly. Bending head attachments of the prior art generally consist of an anvil member provided with support means for rigidly fastening the latter to the main body of a hand power tool driving a reciprocating member. A movable hammer member, generally pivotably mounted on the support means of the head attachment, is articulated by the reciprocating member of the power tool such that its hammer head portion performs a reciprocating movement against the comparatively fixed anvil member. The hammer head and anvil members generally have correspondingly-shaped configurations that can be imbricated into one another such as, for example, two elongated members that are both having V-shaped cross-sections, or half-circular cross-sections, or the like, depending on the desired bend along the sheet metal edge.
In use, the hand power tool equipped with the bending head attachment is turned on and the sheet metal engaging portion of the head attachment is progressively engaged along the peripheral edge of a sheet metal to be bent. As the head attachment is moved longitudinally along the edge, the reciprocating action of the hammer head against the anvil member incrementally bends an edge portion of the sheet metal.
Some examples of the prior art are U.S. Pat. No. 3,777,687, to Colman (1973), U.S. Pat. No. 4,145,907, to Barber et Al. (1979), U.S. Pat. No. 4,176,541, to Cooper (1979), and U.S. Pat. No. 6,578,404 B1, to Rousseau (2003).
While these prior art devices generally offer a bending head attachment for hand-held power tools for longitudinally bending the edge of sheet metal, they also entail one or more of the following disadvantages:                they often leave impact marks or scores along the bent edge;        they are generally designed for a specific thickness of sheet metal;        they generally require a hand-held power tool offering a relatively powerful reciprocating drive member, which are power tools that are relatively less commercially available on the market and, thus, relatively more expensive as compared to rotary drive power tools such as hand-held power drills;        they generally do not allow a bent edge to be reverted to its original planar configuration, such as when a portion of an edge has been bent erroneously, without having to replace selected components of the head attachment, such as the hammer head and/or the anvil members.        
Against this background, there exist a need for a new and improved bending head. It is a general object of the present invention to provide a new and improved bending head.